1. Field of the Invention
The present invention relates to an ink jet recorder, and more particularly to an ink jet recorder capable of recording in multiple colors.
2. Related Background Art
A multi-color ink jet recorder uses black, cyan, magenta and yellow inks, for example, and has ink jet heads for the respective colors. It discharges the inks of the respective colors as dots in accordance with a record command to record a seven-color record on a record sheet by a combination of a plurality of colors.
When such a multi-color ink jet recorder is used, the number of nozzles of the heads may be around 2,000 per color. The diameter of an orifice at the end of each nozzle is very small, for example, several tens of microns, and control of the jetting of droplets is very difficult.
Various mechanisms for jetting droplets in such a color ink jet printer have been proposed. A so-called bubble jet system in which bubbles are forcibly generated at the nozzles and the inks are discharged from the orifices by the rise in ink pressure in the nozzles has been well known.
The ink jet printer of this type can be modular in construction and the modules are removably designed to facilitate maintenance and transportation.
Since the ink jet printer of this type uses liquids inks, non-discharge of the ink may occur by drying of the inks or bubbles due to gases in the inks.
Such non-discharge may be also caused by clog of the orifice by fat or dust deposited when the fingers of an operator contact the head unit when it is mounted or removed.
It has been proposed to cover the head unit when it is mounted or removed so that the fingers of the operator do not contact the head unit.
On the other hand, when the unit is to be mounted or removed, it is necessary to connect or disconnect electrical connections and ink paths. Accordingly, connectors and valves are used so that connection and disconnection are automatically made when the unit is mounted or removed.
The above construction raises the following problem. The attachment and removal of the cover to cover the head, and the electrical connection/disconnection work are independent works which are not related to each other. As a result, even if the cover is attached, the unit may be removed without disconnecting the electrical connection and the electrical connection may be destroyed. Whatever care the operator may pay, such a failure will occur at a certain probability, and the recorder is not usable during such a failure.